Our objectives are to investigate the photochemical behavior of specifically designed organic molecules with the objective of delineating the molecular change occurring as a function of molecular structure and with the added goal of determining how these changes can be controlled experimentally. The effects of irradiation and photochemically induced changes in physiological systems is presently the subject of intense research effort. There is the possibility of understanding and controlling those physiological changes involving light. Additionally, there is the hope of being able to modify physiologically important systems selective by use of ultraviolet light. However, a major limitation is the complexity of natural systems along with the still primitive state of our understanding of the factors controlling photochemistry. By using carefully designed molecules with different types of structural features, we can limit the variables. This has been the philosophy of our approach thus far; and this approach has been very rewarding thus far. Hence we wish to continue our efforts. Our results, we feel, get at the base of understanding and using photochemistry and photobiology. Additionally, in our work we are continually developing new techniques and methodology for photochemistry and photobiology.